Automatic means to control and reverse fluid-operated cylinder-and-piston units



2,698,51 7 -OPERATED Jan. 4, 1955 K. F. WITT AUTOMATIC MEANS TO CONTROLAND REVERSE FLUID CYLINDER-AND-PISTON UNITS 3 Sheets-Sheet 1 Filed May21, 1952 Fig.2

INVENTOR. KENNETH F. W |TT. mam/FM ATT'Y.

K. F. WlTT Jan. 4, 1955 2,698,517 OPE.RATED AUTOMATIC MEANS TO CONTROLAND REVERSE FLUID CYLINDER-AND-PISTON UNITS 3 Sheets-Sheet 2 Filed May21, 1952 QLW. 41% I ATTY K. F. WITT 2,698,517 AUTOMATIC MEANS T0 CONTROLAND REVERSE FLUID-OPERATED Jan. 4, 1955 CYLINDER-AND-PISTON UNITS 3Sheets-Sheet 3 Y Filed May 21, 1952 JNVENTOR.

KENNETH F. WITT.

ATT'Y.

United States Patent AUTOMATIC MEANS TO CONTROL AND RE- VERSEFLUID-OPERATED CYLINDER-AND- PISTON UNITS Kenneth F. Witt, Winchendon,Mass.

Application May 21, 1952, Serial No. 289,042

1 Claim. (Cl. 60-97) This invention relates to fluid-operatedcylinder-andpiston units and to the automatic control and reversalthereof.

It is the general object of the present invention to provide meanscontrolled by the pressure in the active cylinder and effective toreverse the main valve at the completion of a piston stroke in eitherdirection.

I also provide means to control the operation of two cylinder-and-pistonunits simultaneously, but with the pistons moving in oppositedirections. A construction is also shown in which two controlled pistonsoperate successively and in the same direction.

My invention further relates to arrangements and combinations of partswhich will be hereinafter described and more particularly pointed out inthe appended claim.

A preferred form of the invention is shown in the drawings, in whichFig. 1 is a sectional plan view of certain fluid-operated mechanisminvolving my invention;

1Fig. 2 is a sectional elevation of my improved control va ve;

Fig. 3 is a fragmentary sectional elevation showing a slightmodification to be described;

Fig. 4 is a plan view, partly in section, of a duplex mechanism, withthe fluid-operated pistons moving simultaneously in opposite directions;and

Fig. 5 is a view similar to Fig. 4 but showing a pair of pistonsarranged for successive operation in the same direction.

Referring particularly to Figs. 1 and 2, I have shown a power unitcomprising a main cylinder C having a piston P slidable therein andconnected to a piston rod R by which anv desired moving parts may beactuated. The head end of the cylinder C is connected by a passage andpipe 11 to a main valve V2, and the rod end of the cy inder C is similrlv nnected by a passage 12 and pipe 14 to the same valve V2.

Fluid under pressure is supplied to the valve V2 through a pipe 15, andthe valve V2 is provided with exhaust pass ve 16 and 17. A f ur-partiston or spool 20 is freely slidab e in the valve V2, and the valve isconnected at its ends throu h pipes 21 and 22 t special control valvesV3 and V4. A start-and-stop or shut-off valve V5 is supplied in the pipe15, and a valve V6 in a by-pass 24 is provided for a purpose to bedescribed.

The control valve V3 is shown in detail in Fig. 2 and is connected tothe passage 10 in the cylinder C by a short pipe 26. The valve V4 is ofidentical c nstruction and is connected to the passage 12 by a pipe 27.

The valve V3 comprises a piston slidable in a cylinder 31 and normallyheld in the left-hand-position shown in Fig. 2 by a com ression s ring32, which is interposed between a shoulder 33 of the piston 30 and ashoulder 34 at the inner end of an adiusting screw 35. The screw 35 isthreaded in the cylinder 31 and may be gamed in or out to vary thecompression of the spring The screw 35 has an axial recess 36 to looselyreceive the piston rod 37, and the recess has a vent 38 to relieve thepressure therein. At its left-hand end, the piston 30 has an axialprojection 39 which serves as a stop and ghicl'zt checks the piston 30in the position shown in With the associated parts in the position shownin Fig. 1. fluid under ressure from the sup ly pipe 15 will flow throughthe pipe 14 and passage 12 to the righthand or rod end of the cylinder Cwill move the pis- ICC ton P to the left. The tension of the spring 32in the valve V4 is sufiicient to prevent the piston 30 in said valvefrom being moved to the right so long as the piston P is free to move tothe left in the cylinder C.

When the piston P reaches its limit of travel, however, as by engagementwith the end of the cylinder, the fluid pressure will then build up inthe right-hand end of the cylinder C and in the passage 12 and willeventually overcome the spring 32 and force the piston 30 to the rightto uncover the pipe 22.

Strong pressure will then be applied through the pipe 22 to the mainvalve V2 and will shift the piston or spool 20 to its extreme left-handposition, thus reversing the main valve and the supply and exhaustconnections of the main cylinder C and causing the main piston P tobegin its travel to the right.

When the right-hand limit of travel is reached, pressure will build upin the left-hand end of the cylinder C and the valve V3 will thereuponbe opened to supply pressure through the pipe 21 to again reverse thepiston 20 and the main valve V2.

The piston P will thus be reciprocated between its defined limits oftravel in both directions, and the direction of travel will beautomatically reversed at the end of each stroke through the operationof the control valves V3 and V4 and without reliance on reversing dogsor other mechanical or electrical devices.

The only moving control parts are the pistons 30 in the valves V3 andV4, and these movements take place in one direction on the applicationof relatively heavy pressure through one of the pipes 26 or 27, and takeplace in the opposite direction as soon as the pressure in theassociated pipe 26 or 27 is relieved. The entire operation is extremelyreliable and satisfactory.

In Fig. 3, I have shown a needle valve interposed in a small passage 46connecting the pipe 26a to the cylinder C. This needle valve may beadjusted as desired to control the speed of operation of the piston 30in the associated valve V3 or V4.

The valve V6 in the bypass 24 may be opened manually to shift the mainvalve piston 20 to the left at any time and to thus apply pressure inthe head end of the cylinder. If the valves V5 and V6 are both closed,all operations cease.

In the duplex construction shown in Fig. 4, two main cylinders C2 and C3are provided. The cylinder C2 is connected by pipes 50 and 51 to a mainvalve V7 corresponding in all respects to the main valve V2 shown inFig. 1. The right-hand or rod end of the cylinder C2 is connected to themain valve through a pressure-re- .sponsive control valve V8 which isidentical with the valve V3 shown in Fig. 2. The valve V8 is connectedto the cylinder C2 by a pipe 52 and is connected by a pipe 53 to a pipe54 which connects the adjacent ends of the main valve V7 and a secondmain valve V9.

The cylinder C3 is connected by pipes and 61 to said main valve V9,which valve is of the same construction as the main valve V7 (Fig. 4)and the main valve V2 (Fig. 1). Fluid under pressure is supplied througha main supply pipe 63 and branch pipes 64 and 65.

A by-pass pipe 66 is connected into the left-hand end of the main valveV7 and is also connected through a cross pipe 67 to a pipe 68 whichextends from a control valve V10 for the cylinder C3 to the right-handend of the main valve V9.

the pipe 63 between the by-pass pipe 66 and the branch pipes 64 and 65.

In this duplex machine, the pistons 68 and 69 in the cylinders C2 and C3are operated simultaneously but in opposite directions. Consequently,the piston of either cylinder may perform a working stroke while thepiston of the opposite cylinder is performing a return stroke.

By momentarily opening the by-pass valve V11, the main valves V7 and V9may be placed in the positions shown in Fig. 4. If the valve V12 is thenopened, fluid under pressure will flow to the right-hand end of thecylinder C2 and to the left-hand end of the cylinder C3.

The piston 68 will then move to the left and the piston 69 to the rightuntil the pistons reach the ends of their Fatented Jan. 4, 1955respective strokes, whereupon pressures will be built up in the controlvalve V8, and the slidable pistons in the main valves V7 and V9 will beshifted to the left and to the right respectively, to reverse theoperating connections of the main cylinders C2 and C3.

It will be noted that the cross pipe 54 connects the adjacent ends ofthe valves V7 and V9, while the cross pipe 67 similarly connects theoutside ends. Consequently, when the piston 68 completes its stroke tothe left and pressure builds up in the right-hand end of the cylinderC2, the control valve V8 will operate to admit pressure to the pipes 53and 54 and to thus shift the piston in the valve V7 to the left and thepiston in the valve V9 to the right. The piston 68 will then begin amovement to the right and the piston 69 to the left, which movement willcontinue until pressure is built up in the right-hand end of thecylinder C3.

The valve V10 will then admit pressure to the pipes 68 and 67, thusagain reversing the main valves V7 and V9, whereupon the described cycleof operations will start over.

The valve V11 may be manually opened at any time to place the mainvalves V7 and V9 in the positions shown, and the valve V12 may be closedat any time to stop all further operations of the duplex machine.

In the duplex construction shown in Fig. 5, two main cylinders C and C6are provided. The cylinder C5 is connected by pipes 70 and 71 to a mainvalve V14 corresponding in all respects to the main valve V2 shown inFig. 1. The cylinder C6 is similarly connected by pipes 72 and 73 to amain valve V15. Pressure-responsive valves V20 to V23 are provided atthe opposite ends of the cylinders C5 and C6 as shown.

The valve V20 at the closed end of the cylinder C5 is connected by apipe 80 to the right-hand end of the main valve V15. The valve V21 atthe rod end of the cylinder C5 is connected by a pipe 81 to theleft-hand end of the main valve V15. The valve V22 at the lefthand orclosed end of the cylinder C6 is connected by a pipe 82 to the left-handend of the main valve V14, and the valve V23 at the right-hand or rodend of the cylinder C6 is connected by a pipe 83 to the right-hand endof the main valve V14.

Fluid under pressure is furnished through a supply pipe 85 and branchpipes 86 and 87 to the intakes 88 .and 89 for the main valves V14 andV15 respectively.

The usual exhaust connections 90 are also provided for the valves V14and V15. A shut-off valve V25 is provided in the supply pipe 85, and asetting valve V26 is provided in the pipe 70.

Assuming that the parts are in the position shown in Fig. 5, theoperation is as follows:

Fluid under pressure will be supplied through the supply pipe 85, branchpipe 86, intake 88 and pipe 70 to the left-hand or closed end of thecylinder C5, thus forcing the piston P to the right. When the piston hascompleted its right-hand stroke, pressure will be built up in theleft-hand or closed end of the cylinder C5, which pressure willeventually overcome the valve V20 and will admit fluid under pressurethrough pipe 80 to the right-hand end of the main valve V15.

This will move the valve piston to the left and will admit fluid underpressure through the branch pipe 87, intake 89 and pipe 72 to theleft-hand or closed end of the cylinder C6, thus moving'the piston P2 tothe right.

After this stroke is completed, pressure is built up to open the valveV22 and admit fluid under pressure through the pipe 82 to the left-handend of the valve V14, thus forcing the valve piston to the right andadmitting fluid under pressure through the pipe 71 to the right-hand orrod end of the cylinder C5 and thereupon shifting the piston P to theleft.

When this stroke is completed, pressure will be built up in the rod endof the cylinder C5 to overcome the valve V21 and admit fluid underpressure through the pipe 81 to the left-hand end of the valve V15, thusmoving the valve piston to the right and admitting fluid under pressurethrough the pipe 73 to the right-hand end of the cylinder C6, withresultant movement of the piston P2 to the left.

When this movement is completed, pressure will be built up to open thevalve V23 and admit fluid under pressure through the pipe 83 to theright-hand end of the main valve V14, thus returning the valve piston toits original position. Both pistons P and P2 are then in their originalor extreme left-hand positions, and the described cycle of operationswill thereupon be repeated.

The setting valve V26 may be closed as soon as the piston P2 in thecylinder C6 completes its stroke to the left, thus holding both pistonsP and P2 in their extreme left-hand or loading position for as long aperiod as may be desired. All operations may be stopped at any time byclosing the shut-off valve V25.

I have thus provided improved automatic mechanism for controlling themovement and reversal of one or more cylinder-and-piston units entirelyby cylinder pressures and without the use of dogs or other mechanical orelectrical devices.

Having thus described my invention and the advantages thereof, I do notwish to be limited to the details herein disclosed, otherwise than asset forth in the claim, but what I claim is:

In a fluid-operated mechanism, two cylinder-and-piston power units, amain valve for each power unit and having a cylinder with a reversingpiston slidable therein, a pressure-responsive control valve for eachend of each power-unit cylinder, and direct connections from eachcontrol valve of each power unit to one end of the main valve for theother power unit, whereby a substantial rise in pressure in eitherpower-unit cylinder will act directly on the main valve for the otherpower-unit cylinder and will thereby shift said main valve and reversesaid other power unit.

References Cited in the file of this patent UNITED STATES PATENTS1,938,758 Ernst Dec. 12, 1933 1,952,690 Strom, Sr. Mar. 27, 19342,223,792 Muir Dec. 3, 1940 2,287,709 Ringman June 23, 1942 2,342,450Campbell Feb. 22, 1944 2,617,257 Douglas Nov. 11, 1952

